Roncalli Elementary in St. John's, where crews are hoping to complete as much of an extensive renovation as possible, will open several days later than most other schools.
The English School District had hoped to have enough work done at the school to allow it to open next week, in conjunction with other openings.
But the board said it will now open the school on Monday, Sept. 8.
The government approved a $20.7-million expansion of the school in 2012, prompted by concerns of overcrowding and growth in the Airport Heights neighbourhood.
Part of the school remains a construction zone, and fences will be erected to prevent children from gaining access.
"We recognize this delay will be an inconvenience for many families and we do apologize to anyone who may be negatively impacted," assistant director of education Anthony Stack said in a letter sent to parents.
Meanwhile, it's expected that Exploits Valley High School in Grand Falls-Windsor also will not be ready for next week. There is no word yet on when it will open.